A conventional connectionless switched communication system may be used to communicate information within a local area network (“LAN”) and within a storage area network (“SAN”). The LAN can include a plurality of user nodes or computers (e.g. personal computers) coupled to a plurality of servers, via an Ethernet hub or an Ethernet switch. The SAN can include a plurality of mass storage systems and/or devices, such as disk drive systems, tape drive systems and/or optical storage systems, coupled to the plurality of servers, via a Fibre Channel switch for example.
In communicating information from the user nodes to the mass storage systems, the user nodes provide a plurality of data packets in an Ethernet format, which are subsequently received at the Ethernet switch, along with pertinent information related to the address of the destination server. The Ethernet switch buffers the incoming data packets and re-routes the data packet to the indicated server without prior knowledge of traffic patterns. The server receives the data packets from the user node and processes the data packets to reformat the data packets into a Fibre Channel format, which are used for communication with the SAN. The data packets are received at the Fibre Channel switch from the server. The Fibre Channel switch responds to receipt of the data packets by buffering the data packets and re-routing the data packets to the appropriate mass storage device to store the data packets.
Communicating information from the mass storage systems to the user computers is similar to that described above for communicating information from the user computers to the mass storage systems. More specifically, at least one of the mass storage systems can respond to a request for information received from one or more of the user computers by retrieving and packaging previously stored information into a plurality of data packets in a Fiber channel format. The data packets in the Fibre Channel format may be received and buffered at the Fibre Channel switch. Further, the Fibre Channel switch re-routes the data packets to the appropriate server, which is coupled to the user computer that requested the information. In this instance, the server receives the data packets in the Fibre Channel format from the Fibre Channel switch and processes the data packets to reformat the data packets into an Ethernet format, which is suitable for communication over the LAN. The data packets are thereafter received at the Ethernet switch, which again buffers the incoming data packets in the Ethernet format and re-routes the data packets to the user computer that requested the information without prior knowledge of the traffic patterns.
One problem may occur when a plurality of user nodes communicate a plurality of data packets to the Ethernet switch in random bursts, which can cause the buffer associated with the Ethernet switch to overflow. When the buffer of the Ethernet switch overflows, subsequently communicated data packets may be dropped or lost. Temporarily halting receipt of data packets in the Ethernet Switch until the buffer can be emptied avoids the problem of dropping or losing data, however, this approach significantly reduces system performance (e.g. by introducing undesirable latencies into the systems). The Fibre Channel switch can also experience similar problems related to buffer overflows as that described above with respect to the Ethernet switch.
It is not sufficient to simply increase the size of the buffer(s) to accommodate the data packets because this can result in long delays in moving the data packets in and out of the buffer, which also introduces system latencies and seriously degrades system performance. Further, large buffers may be costly and difficult to design in practice, especially for high-speed systems.
Another problem in the above-described conventional connectionless switched communication system is related to the significant overhead processing that is carried out by the servers to convert or re-format the data packets back and forth between the Ethernet format (e.g. suitable for communication over the LAN) and the Fibre Channel format (e.g. suitable for communication over the SAN). Further, system configurations that support both Ethernet and Fibre Channel data formats typically require specific hardware, as described above, for supporting each protocol or data format.
Therefore, an unsolved need remains for a data communication system that can support a plurality of protocols and reduce or eliminate the overhead processing that is carried out by the servers to convert or re-format the data packets back and forth between the Ethernet protocol and the Fibre Channel protocol.